Sumitomo Rubber Industries Limited

Tadahiro Ebisuno

Keiji Moriyama

Kengo Oka

Kazushige Sugimoto

Mikio Yamada

Kuniyasu Horiuchi

Akira Kato

Takashi Sasaki

Akihiko Hamada

Akihiro Nakahara

Yoshikazu Yabuki

Tsutomu Hirau

Yoshiyuki Mimoto

Susumu Yoshida

A coated golf ball has an ionomer cover and a paint layer thereon, wherein an ionomer resin cover substantially contains no fluorescent brightener, Wcie reading which indicates whiteness after coating of the paint is within the range of 110 to 125, Tw reading which indicates greenishness is within the range of 4 to 6.5, and the Wcie (Cw) and Tw (C.sub.T) reading of the cover and the Wcie (Pw) and Tw (P.sub.T) reading obtained after coating of the paint have a following relation:

Golf ball

The present invention provides a thread wound golf ball having improved flight performances, which comprises a solid center, a thread layer and an outer cover. The solid center is formed from a rubber component with crosslinked structure which contains an oily substance. Impact resilience of the solid center is 90 cm or more.

Thread wound golf ball

The present invention provides a thread wound golf ball which keeps good hit feeling inherently holding in thread wound golf balls and attains long flying distance which is equal to that attained by the two-piece solid golf ball. The thread wound golf ball comprises a center composed of a vulcanized molded article of a rubber composition, a thread rubber layer formed on said center and a cover covering on said thread rubber layer, wherein said center has a diameter of 30 to 35 mm and a strain amount formed between an initial loading of 10 kg and a final loading of 30 kg is 1.2 to 2.5 mm. The cover of the thread rubber layer has many dimples thereon and the product of total volume of the dimples and the diameter of the center is 8,500 to 11,000 mm.sup.3.mm.

Disclosed is a thread wound golf ball which includes a liquid center composed of a rubber bag containing a liquid, a rubber thread layer provided on the outside of the liquid center and a cover for covering the rubber thread layer, wherein the moment of inertia measured at 23.degree. C. of the golf ball is 75 to 80 g.multidot.cm.sup.2 and the rate of increase of a moment of inertia measured at -30.degree. C. to that measured at 23.degree. C. is within 2%.

Liquid center thread wound golf ball

Disclosed is a thread wound golf ball having uniform flying performances, which causes little scattering of weight and inclusion of air into the liquid center, wherein no separation of the paste is arisen. The thread wound golf ball comprises a liquid center, a thread rubber layer and a cover. The liquid center is composed of a paste and a center bag for coating the paste. A viscosity at 23.degree. C. (measured by a B type viscometer) of the paste is 15 to 70 poise.

A pair of semispherical molds, each having dimple-forming projections on a connecting portion is used to shape a resinous material into a golf ball having dimples on a seam corresponding to the connecting portion. A ball fixing means is utilized to hold the golf ball thereto with the seam uncovered. A cutting member disposed at an end of a rotary shaft, and having a radius of curvature smaller than a sectional radius of curvature of the dimple is utilized to remove a burr from the seam of the golf ball. The rotary shaft rotates on its axis and moves forward when the cutting member is brought into contact with the dimple on the seam and backward when the cutting member is brought into contact with a convex land portion. The cutting member is then pressed against the seam successively in alternate contact with the dimples and the land portions.

Apparatus and method for manufacturing golf ball

An apparatus for removing the burr from the seam of a golf ball made using a pair of semispherical molds each having dimple-forming projections on a connecting portion to shape resin into a golf ball having dimples on a seam corresponding to the connecting portion. A ball fixing mechanism holds the golf ball thereto with the seam uncovered. A cutting member having a cutting member, disposed at an end of a rotary shaft, having a radius of curvature smaller than a sectional radius of curvature of each of the dimples. The rotary shaft rotates on its axis and moves forward when the cutting member is brought into contact with each of the dimples on the seam and backward when the cutting member is brought into contact with a convex land thereon. Thereafter, the cutting member is pressed against the seam successively removing the burr while maintaining the integrity of each of the dimples.

Apparatus for manufacturing a golf ball

A golf ball (G) comprises a liquid center (1), a rubber thread layer (2) formed around the liquid center (1) and a cover (3) covering the rubber thread layer (2), wherein said liquid center (1) has a diameter (L1) of 29.5 to 32.0 mm and the ratio, Y, of the sum total of the flat surface area (5S) of dimples (5) to the surface area (G-1) of the same sphere having no dimples formed thereon is within the range of 0.80 to 0.84. The total volumes of dimples (5) are in the range of 290 to 340 mm.sup.3. The dimples (5) include a plurality of kinds of dimples having different diameters.

Disclosed is a thread wound golf ball comprising a liquid center, rubber thread layer formed on said liquid center, and a cover covering said rubber thread layer wherein said liquid center has a diameter of 29.5 to 32 mm and said cover has dimples thereon which have total dimple volume of 280 to 340 mm.sup.3.

Thread wound golf balls

The present invention provides a thread wound golf ball having excellent durability, heat resistance and impact resilience, which comprises a core, a thread rubber layer and an outer layer. A thread rubber constituting the thread rubber layer comprising a solid rubber containing a high-cis polyisoprene rubber as a main rubber material and a liquid polybutadiene rubber and/or liquid butadiene-isoprene copolymer rubber as a rubber component.

A golf ball which comprises a spherical surface having a parting line at its equator and having a plurality of dimples formed thereon, wherein the dimples are formed so that the ratio, y, of the sum total of the flat surface area of the dimples to the surface area of the same sphere having no dimples formed thereon is within the range

Disclosed is a large size three piece solid golf ball comprising a center, an outer layer covering said center to form a solid core and a cover covering said solid core, wherein said center has a diameter of 15 to 24 mm and a center hardness of 25 to 50 (JIS-C), prepared from a rubber composition comprising 100 parts by weight of cis-1,4-polybutadiene, 9 to 20 parts by weight of zinc acrylate and 3 to 150 parts by weight of a zinc oxide, said solid core has a diameter of 36 to 40 mm and a surface hardness of 70 to 90 (JIS-C), a difference between the center hardness and the surface hardness of the solid core is 20 or more and the specific gravity of the center and the outer layer has the following relation;

Three-piece solid golf ball

Disclosed is a solid golf ball (including a one piece solid golf ball and another type solid golf ball) which has excellent durability and a high impact resilience, as well as good feeling when struck. The solid golf ball of the present invention is characterized in that a hardness (H) of a rubber portion of the solid golf ball, when measured by a JIS-C hardness meter, decreases with distance from the surface to the center and satifies the following equation;

Solid golf ball

Disclosed is a three-piece solid golf ball comprising a solid core consisting of an inner core and an outer shell surrounding said inner core, and a cover covering said solid core, characterized in that a diameter of said inner core is 29 to 36 mm, a diameter of said solid core is 37 to 41 mm, a central hardness (JIS-C) of the inner core is 25 to 70, a surface hardness (JIS-C) of said outer shell is 80 to 95, a difference between said central hardness of the inner core and said surface hardness of the outer shell is 10 or more, and the relation between the specific gravity of the inner core and the specific gravity of the outer shell satisfies 1.0 &lt;a specific gravity of the inner core .ltoreq.a specific gravity of the outer shell &lt;1.3.

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Nishinomiya, Japan

Tadahiro Ebisuno